1. Field of the Invention
The invention relates to an MEMS (micro-electro-mechanical-system) microphone package, and more particularly to a chip-scaled MEMS microphone package.
2. Description of the Related Art
Referring to FIG. 1, a conventional MEMS (micro-electro-mechanical-system) microphone package 10 includes a substrate 102, a metal cap 101 attached to the substrate 102, an MEMS microphone die 103 mounted on the substrate 102, and a readout IC (integrated circuit) chip 104 also mounted on the substrate 102.
The metal cap 101 has a sound inlet 106 through which the MEMS microphone die 103 receives external sound. The MEMS microphone die 103 has an MEMS sensor (not shown) inside for converting sound into an electrical signal. A bonding wire 105 is connected between the MEMS microphone die 103 and the readout IC chip 104. The readout IC chip 104 provides bias voltage (around 12V) for the MEMS sensor, receives the electrical signal from the MEMS sensor, and drives external low-impedance loading.
The metal cap 101 and the substrate 102 constitute a means for shielding, to protect the MEMS microphone die 103 from RF (radio frequency) interference.
However, the size of the conventional MEMS microphone package 10 does not meet modern mobile electronic device requirements for extreme compactness. Specifically, the dimensions of the MEMS sensor are around 1 mm×1 mm, so the MEMS microphone package 10 containing the MEMS sensor is somewhat large when provided in a compact mobile phone. Furthermore, the MEMS microphone package 10 has a minimum thickness of about 1.1 mm, and therefore can not be applied in ultra-thin mobile phones.